Investigation of CFRP- and GFRP-confined concrete cylinders under monotonic and cyclic loading

Fiber reinforced polymer (FRP) composites have found increasingly wide applications in engineering due to their high strength-to-weight ratio and high corrosion resistance. One important application of FRP composites is as a confining material for concrete, which can enhance both the compressive strength and the ultimate axial strain of concrete. With this respect, the stress-strain behavior of FRP-confined concrete, under both monotonic and cyclic compression, needs to be properly understood and modeled. This paper presents details of an experimental work carried out on concrete cylinders wrapped with FRP materials and subjected to both monotonic and cyclic loading. A total number of 12 FRP confined concrete specimens and 10 control specimens with a diameter of 100 mm and a height of 200 mm were cast and cured under the same conditions, and two FRP materials (carbon fibers (CFRP) and glass fibers (GFRP)) were used for the construction of the FRP jackets. The effect of the type of confinement material, reinforcement ratio based on the jacket stiffness, and type of loading is examined. A model that predicts the behavior of confined concrete, which takes into account the stiffness and effectiveness of different confinement materials is also briefly introduced.